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Neutrinos and Neutrinos and Ultra-High Energy Cosmic RaysUltra-High Energy Cosmic Rays
Dmitry SemikozDmitry SemikozMPI, Munich & INR, MoscowMPI, Munich & INR, Moscow
in collaboration with in collaboration with
F.Aharonian, O.Kalashev, V.Kuzmin, F.Aharonian, O.Kalashev, V.Kuzmin, A.Neronov and G.SiglA.Neronov and G.Sigl
Ultra High Energy \\ Cosmic Rays
IFIC Valencia October 22, 2002
Overview: Introduction Experimental detection of high energy neutrinos:
Under/ground/water/iceHorizontal air showersRadio detection Acoustic signals from neutrinos
Neutrinos from UHECR protons Neutrinos from AGN Most probable neutrino sources Neutrinos in exotic UHECR models Conclusion
IFIC Valencia October 22, 2002
INTRODUCTION
IFIC Valencia October 22, 2002
Extragalactic neutrino flux?
Only ~ 20 neutrinos with energy
E~ 10-40 MeV from SN 1987A
IFIC Valencia October 22, 2002
Why UHE neutrinos can exist?
Protons are attractive candidates to be accelerated in astrophysical objects up to highest energies.
Neutrinos can be produced by protons in P+P pions or P+pions reactions inside of astrophysical objects or in intergalactic space.
Neutrinos can be produced directly in decays of heavy particles. Same particles can be responsible for UHECR events above GZK cutoff.
IFIC Valencia October 22, 2002
Pion production
ee
...
'
i
b
i
b
PP
NN
p
n
20
eepn
Conclusion: proton, photon and neutrino fluxes are connected in well-defined way. If we know one of them we can predict other ones: tottot EE ~
IFIC Valencia October 22, 2002
High energy neutrino
experiments
IFIC Valencia October 22, 2002
Neutrino – nucleon cross section
Proton density
np~ 1024/cm3
Distance R~104km Cross section
N=1/(Rnp)~10-33cm2
This happens at energy E~1015 eV.
~E0.4
IFIC Valencia October 22, 2002
Experimental detection of E<1017eV neutrinos
Neutrinos coming from above are secondary from cosmic rays
Neutrino coming from below are mixture of atmospheric neutrinos and HE neutrinos from space
Earth is not transparent for neutrinos E>1015eV
Experiments: MACRO, Baikal, AMANDA
IFIC Valencia October 22, 2002
MACRO
IFIC Valencia October 22, 2002
4-string stage (1996)
First underwater telescopeFirst neutrinos underwater
IFIC Valencia October 22, 2002
AMANDA-II
depth AMANDA
Super-K
DUMANDAmanda-II:677 PMTsat 19 strings
(1996-2000)
IFIC Valencia October 22, 2002
Experimental detection of UHE (E>1017eV) neutrinos
Neutrinos are not primary UHECR
Horizontal or up-going air showers – easy way to detect neutrinos
Experiments: Fly’s Eye, AGASA
IFIC Valencia October 22, 2002
Neutrino penetration depth
IFIC Valencia October 22, 2002
Radio detection
IFIC Valencia October 22, 2002
e + n p + e-
e- ... cascade
relativist. pancake ~ 1cm thick, ~10cm
each particle emits Cherenkov radiation
C signal is resultant of overlapping Cherenkov cones
for >> 10 cm (radio) coherence
C-signal ~ E2
nsec
negative charge is sweeped into developing shower, which acquiresa negative net chargeQnet ~ 0.25 Ecascade (GeV).
Threshold > 1016 eV
IFIC Valencia October 22, 2002
IFIC Valencia October 22, 2002
GLUE Goldstone Lunar Ultra-high Energy Neutrino Experiment
E2·dN/dE < 105 eV·cm-2·s-1·sr-1
Lunar Radio Emissions from Inter-actions of and CR with > 1019 eV
1 nsec
moon
Earth
Gorham et al. (1999), 30 hr NASA Goldstone70 m antenna + DSS 34 m antenna
at 1020 eV
Effective target volume~ antenna beam (0.3°) 10 m layer
105 km3
IFIC Valencia October 22, 2002
RICE Radio Ice Cherenkov Experiment
firn layer (to 120 m depth)
UHE NEUTRINO DIRECTION
300 METER DEPTH
E 2 · dN/dE < 10-4 GeV · cm-2 · s-1 · sr-1
20 receivers + transmitters
at 1017 eV
IFIC Valencia October 22, 2002
Acoustic detection
IFIC Valencia October 22, 2002
d
R
Particle cascade ionization heat pressure wave
P
t
s
Attenuation length of sea water at 15-30 kHz: a few km(light: a few tens of meters)
→ given a large initial signal, huge detection volumes can be achieved.
Threshold > 1016 eV
Maximum of emission at ~ 20 kHz
IFIC Valencia October 22, 2002
Present limits on neutrino flux
p
IFIC Valencia October 22, 2002
Future limits on neutrino flux
p
IFIC Valencia October 22, 2002
Mediterranean Projects
4100m
2400m
3400mANTARESNEMO NESTOR
IFIC Valencia October 22, 2002
NEMO 1999 - 2001 Site selection and R&D
2002 - 2004 Prototyping at Catania Test Site 2005 - ? Construction of km3 Detector
ANTARES 1996 - 2000 R&D, Site Evaluation 2000 Demonstrator line 2001 Start Construction
September 2002 Deploy prototype line December 2004 10 (14?) line detector complete 2005 - ? Construction of km3 Detector
NESTOR 1991 - 2000 R & D, Site Evaluation Summer 2002 Deployment 2 floors Winter 2003 Recovery & re-deployment with 4 floors Autumn 2003 Full Tower deployment 2004 Add 3 DUMAND strings around tower 2005 - ? Deployment of 7 NESTOR towers
IFIC Valencia October 22, 2002
Baikal km3 project: Gigaton Volume Detector GVD
IFIC Valencia October 22, 2002
IceCube
1400 m
2400 m
AMANDA
South Pole
IceTop
- 80 Strings- 4800 PMT - Instrumented
volume: 1 km3
- Installation: 2004-2010
~ 80.000 atm. per year
IFIC Valencia October 22, 2002
Pierre Auger observatory
IFIC Valencia October 22, 2002
Telescope Array
IFIC Valencia October 22, 2002
MOUNT
IFIC Valencia October 22, 2002
OWL/EUSO
IFIC Valencia October 22, 2002
ANITA Antarctic
Impulsive
Transient
Array
Flight in 2006
IFIC Valencia October 22, 2002
Natural Salt Domes
Potential PeV-EeV Neutrino Detectors
SalSA Salt Dome Shower Array
IFIC Valencia October 22, 2002
Renewed efforts along acoustic method for GZK neutrino detection
Greece: SADCO Mediterannean, NESTOR site, 3 strings with hydrophones
Russia: AGAM antennas near Kamchatka:existing sonar array for submarine detection
Russia: MG-10M antennas: withdrawn sonar array for submarine detection
AUTEC: US Navy array in Atlantic:existing sonar array for submarine detection
Antares: R&D for acoustic detection
IceCube: R&D for acoustic detection
IFIC Valencia October 22, 2002
RICE AGASA
Amanda, Baikal2002
2004
2007
AUGER
Anita
AABN
2012
km3
EUSO,OWLAuger
Salsa
GLUE
IFIC Valencia October 22, 2002
Neutrinos from UHECR protons
IFIC Valencia October 22, 2002
Why neutrinos from UHE protons?
All experiments agree (up to factor 2) on UHECR flux below cutoff. All experiments see events above cutoff!
Majority of the air-showers are hadronic-like
Simplest solution for energies 5x1018 eV < E < 5x1019 eV: protons from uniformly distributed sources like AGNs.
IFIC Valencia October 22, 2002
Active galactic nuclei can accelerate heavy nuclei/protons
IFIC Valencia October 22, 2002
IFIC Valencia October 22, 2002
Photo-pion production
ee
iNN '
p
n
20
eepn
IFIC Valencia October 22, 2002
Parameters which define diffuse neutrino flux
Proton spectrum from one source:
Distribution of sources:
Cosmological parameters:
E
AEF )(
maxmin EEE
3)1( mzD maxmin zzz
0H vac
IFIC Valencia October 22, 2002
Theoretical predictions of neutrino fluxes
WB bound: 1/E2 protons; distribution of sources – AGN; analytical calculation of one point near 1018 eV.
MPR bound: 1/E protons; distribution of sources – AGN; numerical calculation for dependence on Emax
The ray bound: EGRET
IFIC Valencia October 22, 2002
The high energy gamma ray detector on the Compton Gamma Ray Observatory (20 MeV - ~20 GeV)
EGRET: diffuse gamma-ray flux
IFIC Valencia October 22, 2002
Detection of neutrino fluxes: today
i
p
IFIC Valencia October 22, 2002
Future detection of neutrinos from UHECR protons
AGN,1/E
Old sources1/E^2
IFIC Valencia October 22, 2002
Neutrinos from Active galactic
nuclei
IFIC Valencia October 22, 2002
Active Galactic Nuclei (AGN)
Active galaxies produce vast amounts of energy from a very compact central volume.
Prevailing idea: powered by accretion onto super-massive black holes (106 - 1010 solar masses). Different phenomenology primarily due to the orientation with respect to us.
Models include energetic (multi-TeV), highly-collimated, relativistic particle jets. High energy -rays emitted within a few degrees of jet axis. Mechanisms are speculative; -rays offer a direct probe.
IFIC Valencia October 22, 2002
IFIC Valencia October 22, 2002
Neutrinos from AGN core
IFIC Valencia October 22, 2002
Photon background in core Energy scale
E= 0.1 – 10 eV Time variability
few days or
R = 1016cm Model: hot thermal
radiation.
T=1 eVT=10 eV
IFIC Valencia October 22, 2002
Photo-pion production
ee
iNN '
p
n
20
eepn
IFIC Valencia October 22, 2002
Neutrino spectrum for various proton spectra and backgrounds
1/E
1/E2
T=10 eV
1/E2
T=1 eV
E~1018eV
Atm.flux
IFIC Valencia October 22, 2002
Most probable neutrino sources
IFIC Valencia October 22, 2002
Neutrino production in AGN
IFIC Valencia October 22, 2002
Which sources ?
Blazars (angle – energy correlation)
IFIC Valencia October 22, 2002
Optics: SDSS. Most powerful objects are AGNs
500 sq deg of the sky, 14 million objects, spectra for 50,000 galaxies and 5,000 quasars.
Distance record-holder
>13,000 quasars (26 of the 30 most distant known)
IFIC Valencia October 22, 2002
Low energy radiation from AGN is collimated
Typical gamma-factor is
Radiation is collimated in 1/ angle ~ 5o in forward direction.
IFIC Valencia October 22, 2002
EGRET 3rd Catalog: 271 sources
Most of identified MeV-GeV sources are blazars
IFIC Valencia October 22, 2002
All TeV sources are blazars
IFIC Valencia October 22, 2002
Which sources ?
Blazars (angle – energy correlation) Blazars should be GeV loud
IFIC Valencia October 22, 2002
High energy photons from pion decay cascade down in GeV region
IFIC Valencia October 22, 2002
EGRET 3rd Catalog: 271 sources
Only 22 sources from 66 are GeV - loud
IFIC Valencia October 22, 2002
Which sources ?
Blazars (angle – energy correlation) Blazars should be GeV loud ‘Optical depth’ for protons should be large:
pnR
IFIC Valencia October 22, 2002
Bound on blazars which can be a neutrino sources
IFIC Valencia October 22, 2002
TeV blazars does not obey last condition
Indeed, in order TeV blazars be a neutrino sources:
pnR nR
p= 10-28cm2 while = 6.65 x 10-25cm2
CONTRADICTION!!!
IFIC Valencia October 22, 2002
Which sources ?
Blazars (angle – energy correlation) Blazars should be GeV loud Optical depth for protons should be large:
pnR No 100 - kpc scale jet detected (model-dependent)
IFIC Valencia October 22, 2002
Neutrino production in AGN
IFIC Valencia October 22, 2002
Collimation of neutrino flux in compare to GeV flux
IFIC Valencia October 22, 2002
Acceleration of protons to higher energies
IFIC Valencia October 22, 2002
Neutrinos from exotic UHECR
models
IFIC Valencia October 22, 2002
Top-down models
IFIC Valencia October 22, 2002
Z-burst mechanism
Resonance energy E = 4 1021 (1 eV/m) eV
Works only if
meV
Mean free path of neutrino is
L = 150 000 Mpc >> Luniv
IFIC Valencia October 22, 2002
Cross sections for neutrino interactions with
relict background and
IFIC Valencia October 22, 2002
Problem: too high -ray flux
m1 eV (Yoshida,Sigl,Lee,1998)
IFIC Valencia October 22, 2002
Possible solution: local relic overdensitybut factor 20 over 5 Mpc is needed
IFIC Valencia October 22, 2002
Numerical simulations of the possible local neutrino over-density give factor 2-3
IFIC Valencia October 22, 2002
Non-uniform distribution of sources O.Kalashev, V.Kuzmin, D.S. and G.Sigl, hep-ph/0112351
IFIC Valencia October 22, 2002
Sources of both and
IFIC Valencia October 22, 2002
X -> only (Gelmini-Kusenko model)
IFIC Valencia October 22, 2002
IFIC Valencia October 22, 2002
Conclusions Sensitivity of the neutrino telescopes will be increased
in 103-5 times during next 10 years. Now they just on the border of theoretically interesting region.
Secondary neutrino flux from UHECR protons can be detected by future UHECR experiments.
Neutrino flux from AGN’s can be detected by under-water/ice neutrino telescopes. GeV-loud blazars with high optical depth for protons are best candidates for neutrino sources.
Some of exotic UHECR models will be ruled out or confirmed in near future by neutrino data.
IFIC Valencia October 22, 2002
References:
Diffuse neutrino flux. O.Kalashev, V.Kuzmin, D.S. and G.Sigl, hep-ph/0205050
Extragalactic neutrino sources. A.Neronov & D.S., hep-ph/0208248
AGN jet model. A.Neronov, D.S., F.Aharonian and O.Kalashev, astro-ph/0201410
Z-burst model. O.Kalashev, V.Kuzmin, D.S. and G.Sigl, hep-ph/0112351